Mould closure unit with a device for removing injection mouldings

ABSTRACT

A mold closing unit is provided with a device for handling and/or removal of moldings, comprising a supporting element for supporting the device in the area of the mold, an actuating element, by which handling element penetrating into the mold cavity is operable, as well as a drive unit for driving the actuating element. The drive unit drives the actuating element electromechanically and at least drive unit, supporting element and actuating element constitute structural unit which is detachable from the mold closing unit. The drive unit is a hollow shaft motor at least partially receiving the actuating element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the priority of German Patent Application195 36 567.4, filed on Oct. 2, 1995, the disclosure contents of which isherewith also explicitly made the subject matter of the presentapplication.

TECHNICAL FIELD

The invention concerns a mold closing unit comprising a device forhandling and/or removal of injection moldings wherein there is provideda stationary mold carrier; a movable mold carrier displaceable towardsand away from the stationary mold carrier; a mold clamping space formedbetween the movable and stationary mold carriers and adapted forreceiving a mold comprising a mold cavity for manufacture of moldings; asupporting element supporting the device at the mold closing unit; thedevice including a handling element actuatable for penetrating linearlyinto the mold to the mold cavity when handling or removal of moldings isrequired; an actuating element for actuating the handling element; andan electromechanical drive unit for driving the actuating element,wherein the drive unit, the supporting element and the handling unitcomprise a structural unit which is independently detachable from themold closing unit.

PRIOR ART

Such a mold closing unit comprising a device for handling and/or removalof moldings constituted as a structural unit and having multiple uses isknown from DE 42 28 140 A1. It can be tested at the customer's companywith regard to its operatability before the device is installed and canbe transferred from machine to machine, if the customer should requireit. For this purpose the unit has only to be connected to acorresponding connection component in the area of the mold of theinjection molding machine and to a mains supply. The device is drivenvia an electromotor as for example a gear motor, so that a triggeringvia a spur gear takes place. This not only involves an additionalexpenditure, but means that in the space already required for the moldclosing device of the mold closing unit, space for arranging the gearmotor and the gear has to be provided, if an ejector is applied. Thismakes it more difficult to transfer the device to different machines andin some cases even impossible.

From DE 44 09 822 A1, a planetary-rolling-thread-spindle drive is known,which makes possible an extremely precise triggering of the ejector. Inthis spindle drive known as such from EP-B 320 621, planet rolls areprovided, which on the side of the nut, mesh with rills of the nut andon the side of the spindle are in connection with the thread of thespindle. Through a rolling motion, thread pitches up to a range of 0.1mm per each thread pitch are possible. Due to the rolling motion thesedrives have an extremely low noise level, although, a space-robbingseparation between motor and drive is the consequence which is notdesirable in the area of the ejector.

In the field of electro mechanical machines, electrical devices are alsoknown for handling and/or removal of moldings from the injection mold.These known devices mostly have a problem that they cannot worksufficiently precise or that not enough space for the ejectors is atdisposal, since when electromotors are applied, a rotational movementalways has to be converted into a linear movement. The linearly movedelement of the drive then, however, needs a corresponding space at theinjection molding machine. In this field, however, it is unusual to usethe same element as ejector-, core drawback- and unscrewing-device.

A mold closing unit is known for example from DE 82 33 362 U1 forhydraulically working machines. This device serves as an ejector forejecting the moldings manufactured in an injection molding process. Theejector units or alternatively core drawback- or unscrewing devices (DE19 62 663 B2) required therefor, however, are because of space reasons,arranged fixedly in the area of the mold closing unit and are notdisplaceable.

SUMMARY OF THE INVENTION

Based on this state of the art, it is an object of the invention tocreate a space-saving, electromechanically working device for handlingand/or removal of moldings, which is multiply usable as an independant,operative unit.

The above and other objects are accomplished according to the inventionby the provision of a combination of a mold closing unit and a devicefor handling and/or removal of moldings from an injection moldingmachine for processing plastifiable materials, comprising: a stationarymold carrier; a movable mold carrier displaceable towards and away fromthe stationary mold carrier; a mold clamping space formed between themovable and stationary mold carriers and adapted for receiving a moldcomprising a mold cavity for manufacture of moldings; a supportingelement supporting the device at the mold closing unit in an area of themold; the device including a handling element actuatable for penetratinglinearly into the mold to the mold cavity when handling or removal ofmoldings is required; an actuating element for actuating the handlingelement; and an electromechanical drive unit including a hollow shaftmotor at least partially receiving the actuating element for driving theactuating element, wherein the drive unit, the supporting element andthe handling unit comprise a structural unit which is independentlydetachable from the mold closing unit.

According to the invention, a hollow shaft motor is used, as the driverand receives at least partially the actuating element, which preferableis a spindle. The use of a hollow shaft motor in the area of the ejectorhas the advantage that it can be constructed in an extremelyspace-saving manner, since no additional elements for the conversion ofthe rotational movement into a linear movement outside the hollow shaftmotor are required. In the area of the closing mechanism, where it isimportant to transfer the force of the closing device as full face orflush as possible to the movable mold carrier, the hollow shaft motorcan trigger the ejector directly. Since the ejector, does not need nowto be arranged in line with the closing unit, the mold closing unit andthus the injection molding machine is reduced in length. Even in case ofan arrangement in line with the closing device, the structural shape isstill shorter compared to that of other known ejectors. Thus, utilizingthe princples of the invention, the whole injection molding machine canbe more compact and favorable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a top view on an injection molding machine in the area of themold closing unit,

FIG. 2 a side view of a device for handling and/or removal of moldings,

FIG. 3 a top view of the device according to FIG. 2,

FIG. 4 a view of the movable mold carrier plate, with the closing unitis in section,

FIG. 5 an illustration according to FIG. 2 showing a direct fixing ofthe device at the mold carrier,

FIG. 6 a side view of an arrangement of the device on the injectionmolding side,

FIG. 7 a top view on the arrangement according to FIG. 6,

FIG. 8 a side view on a mold closing unit comprising two devices fixedthereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will now be described in more detail by example withreference to the figures. The embodiments are merely examples and arenot intended to limit the inventive concept to any particular physicalconfiguration.

FIG. 1 shows a partial view of an injection molding machine forprocessing plastifiable masses, powdery masses or ceramic masses,wherein mostly it is useful as a plastics injection molding machine. Inthis device a mold clamping space R is created between a stationary moldcarrier 11 and a movable mold carrier 12, which is displaceable via aclosing unit. Molds M comprising a mold cavity 14 for manufacturingmoldings 10 are introduced into this mold clamping space. For thispurpose an injection molding unit S, which injects the plastifiablematerial into the mold cavity, is arranged at the stationary moldcarrier 11 or in the parting plane. In order to generate the closingforce, the closing unit is supported at a supporting element 27. Betweensupporting element 27 and movable mold carrier 12, preferably in thecenter of the injection axis, a space is provided for arrangement of anejector, a core drawback or an unscrewing mechanism which are describedbelow as constituted by a device 13 for handling and/or removal ofmoldings.

FIG. 2 shows such a device. The device 13 has an actuating element,which is illustrated in the form of a spindle 15, by which a handlingelement (ejector) 17 penetrating linearly into the mold M to the moldcavity 14 is actuable. In order to make possible this penetration, themovable mold carrier as illustrated in FIG. 2 is provided with a borehole 12 and the mold M has a bore hole 32. The handling element isattached to the wall of the mold cavity 14, in order to have access tothe molding 10 on one side and for, if possible, not being perceptive tovision at the molding 10 after this has been finished. Such a device 13is only used, when the corresponding mold M requires it. The device 13supports itself in the area of the mold, that means at the mold itself,at the stationary mold carrier or at the movable mold carrier.

Electromechanical drive unit A for the spindle 15 is provided in theform of a space-saving hollow shaft motor. The whole device is sodesigned, that at least the drive unit A, the supporting element 27 andthe actuating element 15 constitute a structural unit closed in itselfand detachable as an independant unit from the mold closing unit F. Thisstructural unit is transferable as often as desired,if the correspondingconnections are provided at the injection molding machine on the onehand for mechanical connection of the device 13 and on the other handfor connection to the power supply. Different connections can bedistributed across the machine in the area of the mold M, which then canbe triggered on the control side via a corresponding interface.

The structural unit has coupling means 18 (see example, FIG. 2) by whichthe spindle 15 is couplable as the actuating element to the handlingelement 17. This has the advantage that corresponding ejectors can beexchanged with the mold or that the handling elements according to theirtask as ejectors, core drawbacks or unscrewing mechanisms can beexchanged. A path measuring device 19 is connected with the structuralunit, for example in the form of a linear potentiometer. The drive unitA can be regulated or controlled by the signals of this path measuringdevice 19.

According to FIG. 2 the drive unit A is placed at a distance from themold M. The drive unit, in this case due to reasons of space, a hollowshaft motor, is flanged to a retaining plate 20. In the embodiment ofFIG. 2 the fixing of the retaining plate 20 is made at a formed onelement 12a of the movable mold carrier.

An alternative embodiment is shown in FIG. 5. There the motor is flangedto a retaining plate 20, however, the studs 21 are fixed directly at themovable mold carrier via fixing means 30. This fixing method makeseasier the displacement of the device 13, for example into the positionaccording to FIG. 7 and 8.

In the illustrated embodiment, the drive unit is a spindle drive. Asspindle drives, for example, roll spindle drives, ball roll spindledrives, rolling drives or planetary-roll-thread-spindle drives can betaken into consideration. In the area of the hollow shaft motorplanetary gears can be integrated. If the spindle 15 is actuated, itmoves inside the hollow shaft motor, for which a recess 28 is providedthere. In the embodiments the spindle 15 is fixed secured againstturning at a bearing 22, whilst the nut 16 rotates. The bearing 22 alsomakes sure, that the spindle 15 remains secure against turning.According to FIG. 4 at least two of the studs 21 are at the same timeformed as guide columns, on which the bearing 22 slides. The bearing 22additionally has a formed on element 22a, which makes possible theconnection to the path measuring device 19. At the bearing 22 also thecoupling area K for the coupling means 18 for coupling the handlingelement 17 is arranged.

If a planetary-rolling-thread-spindle drive is provided as the spindledrive, the spindle drive can be triggered very precisely. In this drivemode planet rolls are provided between nut 16 and spindle 15, which withits different outer diameters sit close to rills of the nut 16 and atthe thread of the spindle 15. Low thread pitches and high forcetransformation can thus be realized and in addition the drive is of lownoise.

Since the device 13 comprises a structural unit, it is easilydisplaceable in the area of the mold closing unit and can be arranged,for example, at the stationary mold carrier without problems. Anextremely advantageous arrangement results, if the device 13 in thiscase emulates the injection molding unit S, which in this kind ofarrangement usually is in the parting plane, in order to carry out adirect injection into the parting plane. For this purpose the device 13is connected to a transverse bar 23 (see FIG. 7) via fixing means 30. Atthe transverse bar 23 rod-like components 24 are arranged, which arefixable in connection members 25, usually provided for the fixing of theguide rods 26 of the injection molding unit S. The device 13 is arrangedin such a way, that it lies in the injection axis, so that it canpenetrate into the mold clamping space R through the injection orifice11a of the stationary mold carrier.

FIG. 8 makes clear the advantage of the modular concept obtained withrespect to the device 13. On the one hand a device 13 can be arranged asusual at the movable mold carrier 12. In case of corresponding moldings10 it is possible to arrange a further device 13' at the same time atthe mold M for example. The two devices in the present case merelydiffer from each other in that for the device 13' an embodimentaccording to FIG. 5 has been chosen, so that a fixing of the studs 21 tothe mold is made via the fixing means 30. The fixing means 30 are inconnection with a fixing plate 31, which itself is fixed at the mold M.

The devices 13 can easily be adapted to different intended purposes. Ifit works as ejector or core drawback, it is not necessary, that thehandling element 17 rotates. It is different, however, if the device 13is required as an unscrewing mechanism for unscrewing moldings providedwith a thread. In this case the spindle 15 should rotate. This is madepossible by using the nut 16 as a coupling to the spindle 15 via a setscrew. A guide thread then provides for the necessary advance. Basicallyit is possible that the spindle rotates, if only a corresponding pivotbearing is provided in the area of the bearing 22.

Thus the device is constructed in a modular way and designedelectrically ready to plug including the path measuring device 19.Through the studs 21 formed as guide rods the structural unit bearsitself. By this it can be transferred without problems from machine tomachine. At the same time it is also usable as a core drawback unit. Theconstruction makes possible to maintain the full force over the wholestroke at constant speed. Nevertheless, due to its modular construction,the device 13 is for example also usable in hydraulic machines.

It is self-evident, that this description can be subject to differentmodifications, changes and adjustments, ranging within the area ofequivalents of the annexed claims.

What is claimed is:
 1. A combination of a mold closing unit and a devicefor handling and/or removal of moldings from an injection moldingmachine for processing plastifiable materials, comprising:a stationarymold carrier; a movable mold carrier displaceable towards and away fromthe stationary mold carrier; a mold clamping space formed between themovable and stationary mold carriers and adapted for receiving a moldcomprising a mold cavity for manufacture of moldings; a supportingelement supporting the device at the mold closing unit in an area of themold; the device including a handling element actuatable for penetratinglinearly into the mold to the mold cavity when handling or removal ofmoldings is required; an actuating element for actuating the handlingelement; an electromechanical drive unit including a hollow shaft motorat least partially receiving the actuating element for driving theactuating element, wherein at least the drive unit, the supportingelement and the actuating element form a structural unit which isindependently detachable from the mold closing unit.
 2. The combinationaccording to claim 1, wherein the structural unit includes a pathmeasuring device for producing signals which are useable to regulate thedrive unit.
 3. The combination according to claim 1, wherein thesupporting element comprises a retaining plate at which the drive unitis fixed, and the combination further includes studs arranged tomaintain the retaining plate at a distance from the mold.
 4. Thecombination according to claim 3, wherein the drive unit is fixable atthe movable mold carrier via the studs.
 5. The combination according toclaim 3, wherein the drive unit is fixable at the stationary moldcarrier via the studs.
 6. The combination according to claim 3, furthercomprising means for coupling the actuating element to the handlingelement in a coupling area; and a bearing guided on the studs forguiding a linear movement of the actuating element.
 7. The combinationaccording to claim 1, wherein the structural unit is fixed at thestationary mold carrier.
 8. The combination according to claim 7,further including connection components arranged at the stationary moldcarrier for fixing guide rods of an injection molding unit, and asupporting arrangement for fixing the structural unit to the connectioncomponents, and wherein the actuating element penetrates into the moldclamping area through an injection orifice in the stationary moldcarrier.
 9. The combination according to claim 1, wherein the devicecomprises an unscrewing device and the drive unit includes a rotatablespindle.
 10. The combination according to claim 1, wherein the devicecomprises a core drawback device.
 11. The combination according to claim1, wherein the device comprises an ejector.